No, sleep button is the only one that generates events through hpqlb. On the
other hand, besides the brightness keys, there are only two other fn-keys:
also the display switch works fine with the normal ACPI and the purpose of
the other button has been unclear to me (audio-keys are handled outside ACPI
and can be controlled via e.g. xmodmap).

For me, the driver makes the hotkeys generating events at all.
It also injects volume keys into the audio(4) framework.
> In any case, nice work.
Tnx.
Christoph